Lamp basing apparatus



July 29, 1958 c, BECK 2,845,107

LAMP BASING APPARATUS Original Filed Dec. 26, 1951 I 2 Sheets-Sheet 1 Inventor: Charles E. BecK His Attorney July 29, 1958 c. E. BECK LAMP BASING APPARATUS Original Filed Dec. 26, 1951 2 Shee ts-Sheet 2 Inventor: Charles E. BecK His Attorney United States Patent G 2,845,107 LAMP BAsnsc APPARATUS Charles E. Beck, East Cleveland, Ohio, assignor to General Electric Company, a corporation of New York; patent dedicated to the Public insofar as it relates to lamps and lamp parts to the extent stated in document recorded in the United States Patent Oflice, January 4, 1954, Liber ill-238, page 394 Original application December 26, 1951, Serial No. 263,438. Divided and this application December 22, 1953, Serial No. 399,742

1 Claim. c1. 153-1 application Serial No. 263,438, filed December 26, 1951,

now Patent No. 2,733,419, and assigned to the same assignee as the present invention. 7 p

A base for an incandescent lamp generally comprises a metal shell having its cylindrical surface threaded and an end contact or eyelet insulated from the base proper.

The base is applied to the neck of the bulb, that is to the constricted and generally cylindrical extension of. the main spherical portion of the bulb, and is usually cemented to it. The external contact surfaces for energizing the filament of the lamp are the end contact or eyelet and the shell of the base, these being connected to the lead-in wires which project into the bulb and supportthe filament.

The lead-in wire which is connected to the end contact is generally known as the top lead-in wire whereas the other which is connected to the shell is generally known as the side lead-in wire. My invention is more particularly concerned with a means for connecting the side lead-in wire to the shell of the base without, the use of solder. It is possible to make a contact connection by using a bulb having a full blown seal and pressing a tight fitting base on it so as to wedge the side lead-in wire between the seal shoulder and the shell of the base. However, this solution is diflicult to realize effectively due to the manufacturing tolerances in producing the bulbs and the bases. As a result, some bases will be too small to seat squarely on the bulb neck, while others will be too large to achieve a good contact connection with the leadin wire. A solution to this problem is presented in the co pending application Serial No. 263,457, filed December 26, 1951, of C. E. Bechard et 211., now abandoned, in favor of continuation-in-part application No. 313,276, filed October 6, 1952, entitled Electric Lamp, now Patent No. 2,732,878, and assigned to the same assignee as the present invention. In that application it is proposed to form an indentation in the shell of the base which crosses over the lead-in wire and causes the wire to become embedded in the resulting ridge on the inside of the shell. My invention provides an improved apparatus for making a specific type of indentation which assures a more reliable Another object of my invention is to provide equipment adapted to operate in conjunction with prior art lamp finishing machines for carrying out the method of my invention.

In accordance with my invention, the lamp assembly preferably comprises a bulb having a full blown seal, that is, a seal which conforms closely to the inner diameter of the skirt or edge of the base over a substantial width. The side lead-in wire is drawn out along the outside of the seal and passes between the seal and the shell of the base. In the region where the side lead-in wire emerges from between the seal and the shell of the base, the shell is peened inwardly along a line transverse to the direction in which the lead-in wire lies, The peening effects an inward indentation in the metal of the shell which appears on its inside surface as a raised line or ridge.- This ridge traverses the lead-in wire which becomes slightly embedded in it at the crossover point, resulting in a firm electrical contact. I havefound that it is possible to peen the base and form such an indentation, despite the fragile nature of the bulb which supports it, by means of a high-speed pointed vibratory tool such as an electrical vibrator for engraving metals. With this device, it is possible to deform inwardly the metal of the base without danger of breaking the neck of the bulb, because a high stress is developed on a small area of the base at each blow of the tool but the resultant pressure averaged over the whole of the base is relatively light.

For further objects and advantages and for a better understanding of the invention, attention is now directed to the following description and accompanying drawings. The features of the invention believed to be novel will be more particularly pointed out in the appended claim.

In the drawings:

Fig. 1 is a side sectional view through the neck portion of an incandescent lamp and illustrating the manner of peening the base by means of a vibratory engraving tool;

Fig. 2 is a side view of the lamp seen at right angles with respect to the view of Fig. 1 and showing the line of indentation traversing the side lead-in wire;

Fig. 3 is a plan view of a peening mechanism operating in conjunction with a prior art type of lamp finishing machine for manufacturing electric lamps in accordance with the invention;

Fig. 4 is a side elevation of the peening mechanism;

Fig. 5 is a perspective view of cams for actuating the peening mechanism.

The invention'will be described with reference to an ordinary screw base of the type generally used for household incandescent lamps. It will be understood, however, that the invention is equally applicable to different types of bases; for instance, the invention may be used with bayonet type bases wherein it is desired to effect a connection between between the side lead-in wire and the straight-walled cylindrical shell of the base.

Referring to Fig. 1 which illustrates the fastening of the base in the case of an ordinary incandescent lamp, the base 1 is mounted on the constricted lower portion or neck 2 of an evacuated glass lamp bulb of which a fragment is shown at 3. The bulb may be of conventional construction and containing a filament (shown in Fig. 3)

mounted within it on the ends of the lead-in wires 4 and 5 which enter the bulb through a glass press 6.

The base proper comprises a threaded metal shell 7, an insulating body or web 8, and an end contact 9 fastened to the upper surface thereof. The insulating web 8 may be made of glass in accordance with the common practice or it may be made of a thermal setting plastic. The base is fastened to the neck of the bulb by means of a cement as indicated at 10. Previous to the assembly of the base to the bulb, a quantity of cement is disposed within the base as an annular ring preferably located a slight distance inwardly from the edge or skirt Patented July 29, 1958.

of the shell. A base having such a disposition of cement is generally termed a deep filled base and it permits maintaining the inner lower edge or skirt of the shell free and clear of cement. This is particularly desirable for a lamp structure in accordance with the present invention because a contact connection is desired between the. skirt of the shell and the side lead-in wire, and the basing cement is an insulator which. would interfere with such a connection were it allowed to enter the contact region. The external connections to the lamp are made through the end contact 9 and the shell 7 of the base. The top lead-in wire 4 may be soldered to the end contact in the usual manner as indicated at 11.

The invention is more particularly concerned with the means whereby the connection between the side lead-in wire 5 and the shell 7 of the base is effected. As illustrated in Fig. 1, the seal region of the neck comprises an end portion 12 which is generally annular and perpendicular to the axis of the bulb. Adjacent the annular PQrtion 12 is a generally cylindrical portion 13 of a diameter slightly less than the root diameter of the threads of the base in order to permit the disposition of the cement therebetween. The cylindrical portion 13 merges into the main body of the neck through a shoulder including an expanded cylindrical portion 14 and a conical or flaring portion 15.

The connection between the side lead-in wire 5 and the shell 7 of the base occurs at 17 between the skirt of the shell -and the expanded cylindrical portion 14. The outer diameter of the portion 14 and the inside diameter of the shell are proportioned to give a reasonably tight fit in the region 17. However, I have found that where reliance is placed solely upon a tight fit between the seal shoulder of the bulb and the skirt of the base in order to effect a contact connection between the lead-in wire and the shell, a relatively large number of defective lamps occur. The reason for this is that the lead-in 'wire is quite fine, and if there is any appreciable variation in either the expanded portion 14 or in the skirt of the base, either a loose fit will occur and the connection will be intermittent, or a tight fit will prevent the base from sitting squarely on the bulb. Since both the bulb'and the base are mass produced, manufacturing tolerances will allow variation to occur, and it is generally not feasible to attempt to reduce the tolerances to the extent required to assure the manufacture of lamps with a reasonable low shrinkage or loss factor. In the case of the bases particularly, they are made through a drawing operation which leaves considerable room for variations. Under certain circumstances, the actual circumference of any one base may vary by as much as 5% from the mean or design circumference. It will thus be seen that in commercial production it is simply not feasible to rely solely upon the dimensioning of the seal and of the base to achieve a contact connection by a tight fit.

In accordance with the invention, a firm and reliable contact connection is obtained by peening the skirt of the base inwardly against the seal shoulder and along a line transverse to the side lead-in wire as shown at 18 in Fig. 2. The peening may be performed by means of a small vibrator 21 comprising a head or chuck 22 which is reciprocated backwards and forwards at a high speed in the direction indicated by the arrow 23. The vibrator may, for instance, be an electric engraving tool or a small pneumatic air hammer. A suitable electrical vibrator is marketed by the Burgess Vibrocrafters, Inc. of 180 North Wabash Avenue, Chicago 1, Illinois. For peening the base, I prefer to provide a slightly rounded or ball point tool 24 which is secured in the chuck 22.,

The stroke of the point may be adjusted by means of the knurled nut 25 and I have found that a stroke of approximately of an inch is generally satisfactory for a medium size base made of aluminum.

The peening may be done by swinging the ball point along the circumference of the shell parallel to its rim so as to give a line of small indentations which is transverse to the direction in which the lead-in wire lies and passes over it. This may readily be seen in Fig. 2 wherein the line of indentations 18 crosses over the side lead-in wire 5 which has been indicated in dotted outline. With a high-speed vibrator, it is possible to deform the metal of the base inwards because it places a high stress on a very small area of the base .at a particular moment. Nevertheless the average pressure applied by the tool is relatively small and may be as little as a few ounces. When it has previously been attempted to perform the same peening operation by means of a single blow of a chisel applied to the base, a much higher force is required. Likewise, if the indentation is made by means of a sharpedged roller, a considerably greater constant force must be applied. With a high-speed vibrator the average pressure applied against the base is so small that breakage of lamps during the peening operation is practically nonexistent and shrinkage is insignificant.

Referring to Fig. 2, it will be observed that the inwardly peened furrow 18 consists of a series of minute indentations. At the point 20 where the furrow crosses over the side lead-in wire 5, the wire becomes slightly embedded in the ridge which is produced on the inside Of the shell and a firm contact connection is thereby assured. Each minute indentation was made by a blow of the ball point 24. With the vibrator 21 which has been described, light blows are struck per second. By adjusting the rate at which the 'ball point is swung along the circumference of the base, the points of indentation may be made to occur so close together as to result in a substantially continuous furrow as indicated.

Referring to Figs. 3 and 4, there is shown a base peening mechanism adapted to operate in conjunction with a prior art lamp finishing machine for the manufacture of incandescent lamps in accordance with my invention. The finishing machine may be similar to that described in U. S. Patent 1,708,756, Pagan, and comprises a turret or reel, of which a fragment is shown at 27, having mounted on its periphery a plurality of lamp holding fixtures or heads 28. It will be understood that suitable means are provided for rotating the reel in a counterclockwise direction as indicated by the curved arrow 29. Such means i may comprise a supporting shaft and an intermittent drive mechanism adapted to advance the holders to successive stations for each indexing movement.

The lamp holding head 28 comprises a top plate 30 having an opening or recess 31 for receiving the end contact 9 of the base, and a cup 32 mounted on a spindle 33 which is biased upwardly by a spring 34. Th

cup 32 urges the lamp upward and forces the base to seat firmly on the neck of the bulb. A pair of spring-loaded jaws 35 and 36 pivot together to encompass the base on opposite sides and assist in straightening it on the neck of the bulb.

The base peening mechanism is mounted at a suitable station and comprises a platform 37 which is supported off a standard 38 by means of a straight link 39 hinged to the standard at 40, and a bell crank link 41 hinged to the standard at 42 through a bracket 43. The bell-crank converts the up and down movement of a connecting rod 44 into a horizontal reciprocation of the platform. The connecting rod is pulled down at the appropriate moment during the cycle of the machine in order to move the vibrator forward into engagement with the base of the lamp. It will be understood that the movement of the connecting rod 44 may be obtained through the usual cam 44' and rocker 45 connected to the drive shaft 46' of the machine. The collar 45 and tension spring 46 permit excess motion of the connecting rod without further movement of the platform and the strength of spring 46 determines the pressure exerted by the vibrator point against the base.

The vibrator 21 is fastened to a plate 48 which is pivotally mounted at 49 on the platform 37. During the interval of time when the vibrator engages the circumference of the base, plate 48 is pivoted on platform 37 in order to swing a ball point 24 against the circumference of the base and produce the line of indentation. The pivoting of the plate 48 is achieved through the linkage comprising pin 50, bell crank 51, and connecting rod 52. The bell crank is pivotally mounted at 53 on a bracket 54 fixed to the standard 38, and carries pin 50 on an oiTset portion 55. The lower end of the pin rides in a slot 56 in the end of plate 38 in order not to interfere with the horizontal movement of platform 37 and plate 4 8. The

bell crank is pivoted by the connecting rod 52 whose vertical movement is translated through the crank and the pin into a horizontal pivoting of plate 48. It will be understood that connecting rod 52 may be reciprocated vertically by means of the usual cam 52' and rocker 53' connected to the drive shaft 46' of the machine in order to swing the vibrator point across the base during a suit able interval in the indexing cycle.

I have found over a period of continuous production that lamps constructed in accordance with the invention have a maintenance substantially as good as those constructed in accordance with prior art practice wherein the side lead-in wire is soldered to a brass base. My invention, by eliminating the use of solder, permits the use of more readily available metals, such as aluminum, for the shell of the base. It will be readily realized that this is a considerable advantage which in itself would justify the use of my invention, and in addition, the manufacturing process embodying my invention is generally more economical than the soldering process utilized in the prior While a preferred apparatus of my invention has been shown and described, it will be understood that various modifications may be made without department from the invention. The appended claim is intended to cover any 6 such modifications coming within the true spiritand scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

Lamp manufacturing apparatus comprising means for holding at a peening station a glass bulb with a base fi tted thereon and a lead-in wire wedged between said bulb and base and extending longitudinally therebetween and with the bulb and base oriented to present said lead-in wire at a predetermined angular position in said holding means, a vibrator mounted at said station in a position to be located in apposition to the side of said base in which said lead wire is wedged, a peening tool fastened to said vibrator, means for first advancing said vibrator toward said holding means to cause said tool to engage the side of the base of a lamp presented at said station, and means for then moving said vibrator transversely of said holding means to carry said tool around a portion of the circumference of said base and across said lead-in wire, and means for actuating in proper time relation said means for advancing the vibrator and said means for moving the vibrator.

References Cited in the file of this patent UNITED STATES PATENTS Guenthart Sept. 6, 192.7 

